This invention relates to a thread cutter for a sewing machine equipped with a plurality of needles which can be used for sewing slender tubular articles such as sleeves of clothing and, particularly, to a thread cutter for a sewing machine of a type which is provided with a cylindrical arm having a small diameter, wherein the cloth being sewn is fed along the axis of said cylindrical arm, and a plurality of needles which are disposed along a direction which is orthogonal to the axis of the arm.
Various types of thread cutters for sewing machines have been proposed so far. While there has been known a thread cutter which can be mounted in a cylindrical arm and can be used in a sewing machine having a plurality of needles disposed along the axis of the cylindrical arm, there has not been known one which can be used in a sewing machine of a type wherein the diameter of the cylindrical arm is small and the needles are disposed along a direction which is orthogonal to the axis of the arm. The reason why a thread cutter is not provided for in this type of sewing machine is that a knife of the thread cutter should be advanced or retracted, avoiding the motion of feed dogs, in a direction along which the needles are aligned and there is not enough space for the thread cutter to be disposed in the arm if said arm has a small diameter, since the driving device for the knife of said thread cutter is complicated and requires a large space. For such reasons, this type of sewing machine provided very low working efficiency since threads were cut manually by operators.